function map(el){
this.el=el//game部分已经引用过，所以不需要qs
this.width = 800
this.height =400
}
map.prototype.create =function(){
    this.el.style.width=this.width+"px"
    this.el.style.height=this.height+"px"
    this.el.style.background="url(./bg.png)"
    this.el.style.border="10px solid green"
    this.el.style.position="relative"
}